Tor Browser (Anonimity Browser Bundle)Description
[notation release from torproject.org]
Bundle The Tor software protects you by bouncing your communications around a distributed network of relays run by volunteers all around the world: it prevents somebody watching your Internet connection from learning what sites you visit, it prevents the sites you visit from learning your physical location, and it lets you access sites which are blocked. The Tor Browser Bundle lets you use Tor on Windows, Mac OS X, or Linux without needing to install any software. It can run off a USB flash drive, comes with a pre-configured web browser, and is self-contained. The Tor IM Browser Bundle additionally allows instant messaging and chat over Tor. If you would prefer to use your existing web browser, install Tor permanently, or if you don't use Windows, see the other ways to download Tor. Freedom House has produced a video on how to find and use the Tor Browser Bundle. If you don't see a video below, view it at Youtube

Detailed Download
To start using the Tor Browser Bundle or Tor IM Browser Bundle, download the file for your preferred language. This file can be saved wherever is convenient, e.g. the Desktop or a USB flash drive.
If you have an unreliable Internet connection, it may be easier for you to download the bundle edition which is split up into smaller parts.
Tor Browser Bundle for Windows with Firefox (version 2.2.34-1, 16 MB)